Unfortunately, most of the makeup we put on our face isn't actually very good for it. Petroleum ingredients such as mineral oil along with propylene glycol, both commonly found in foundations and concealers, are associated with skin irritation, eczema and dermatitis. Dimethicone, another common ingredient in mineral foundations and concealers, covers pores, actually suffocating them and locking in bacteria that can fester into acne. Bismuth oxychloride, a filler that's used in almost every brand of mineral makeup is a known irritant that clogs pores, irritates skin and worsens acne.